Drilling jig



J. WEEDY DRILLING JIG Sept. 10, 1940.

Filed Dec. 6, 1959 Patented Sept. 10, 1940 2,214,686

UNITED STATES PATENT OFFICE I j 2,214,686 r DRILLING .IIG p James Weedy,East Molesey, England, assignor to The Renold and Coventry Chain CompanyLimited, Didsbury, Manchester, England, a British company ApplicationDecember 6, 1939,,Serial No. 207,934 InGreat Britain January 27, 1939.In various industries it is often necessary to convex curved surface,being secured at its ends drill a number of holes at precisely spacedinterby any suitable means such as clamps.

vals in objects having curved surfaces. One ex- Figures 3 and 4 areviews similar to Figures 1 ample is the drilling of holes in profiledaircraft and 2 of another form of the invention. In this niembers suchas wing ribs. Hitherto it has been construction the inner links l2, I6are replaced necessary to provide a separate drilling jig for byhardened blocks 22 formed with holes 24 for each contour with the resultthat in some cases guiding the drill.

a very large number of separate jigs is required. Figure 5 represents afurther development of The present invention aims at providing a jigthis form of the invention in which there are 10 which will serve for alarge number of different two rows of blocks 22 which are staggered, the10 contours thereby very considerably reducing the sideplates l0 beingalso staggered. Such a jig number of jigs required in circumstances suchas enables two rows of holes to be drilled at the are indicated above.same time, or a single row of holes at half the According to the presentinvention a drilling pitch of the chain shown in Figure 4, this being orlike jig comprises a number of bushings coneffected by moving the jiglaterally after drilling 15 nected together end to end by pivoted jointsin one row of holes. It is evident that the jig of the manner of atransmission chain. It is evi- Figures 1 and 2 could be'made double ormultiple dent that a jig made in this way can be stretched Width withtwo or more sets of rollers to enable over a convex curved surface ofany contour with two or more rows of holes to be drilled at the each ofthe bushes in close contact with the sursame time, but in this case theholes would not 20 face to be drilled. be staggered.

Preferably, standard transmission chain parts Figures 6 and '7 are viewssimilar to Figures 1 are used in the construction of the jig. In apreand 2 of a jig consisting of a chain having inner ferred form of theinvention the jig resembles links l2, l6 and outer links H), M'Wlthblocks 26 an ordinary transmission chain with the usual provided withhardened bushing 28 inserted into 25 cylindrical rollers replaced bygrooved rollers, the the inner links. Here again the chain might beprofile of the grooves being circular arcs and made double or multipleWidth to provide more the diameters of the rollers being such that thethan one row of bushing. This construction has arcs of any twosuccessive rollers are concentric. the advantage that an existing chainof the cor- 0 Thus, each of the gaps between the rollers is cirrectpitch can be used and blocks with bushes 3o cular in profile and forms aguide for a drill of of different diameters can be used with it interthecorresponding diameter, each bushing being changeably. v constituted bythe adjacent parts of two succes- Figures 8 and 9 illustrate a jig inwhich one sive rollers. The advantage of this form of jig of thesideplates I2 of each inner link, and also is that as the rollers arefree to rotate the wear one of the sideplates ill of each outer link, is

of the surfaces of the grooves is distributed over formed with anextension 30 which is bent at a large area with the result that the jighas a right angles to form a platform in which a hardmuch longer lifethan those in which the drill ened bushing 32 is inserted. The parts areasis guided by ordinary bushing. sembled so that these platforms 3B areturned in- 40 Referring to the accompanying drawing, Wards, the centresof the bushing being on the 40 Figures 1 and 2 illustrate a preferredembodicentre line of the chain. ment of the invention, Figure 1 being aside ele- In Figures 10 and 11 the parts are shown asvation of a part ofthe chain and Figure 2 being sembled with the platforms turned outwards.It a plan. The jig is constructed like a transmisis evidentthat some ofthem may be turned in- 5 sion chain, with outer sideplates I 0, innersidewards and some outwards so as to provide any plates l2, studs l4,bushings I li and rollers I 8. desired staggered arrangement. If, forexample,

The rollers are of such a diameter that they all the platforms belongingto inner links are nearly meet and they are grooved as shown clearturnedinwards and those belonging to outer ly in Figure 2 so that the profileof the grooves links turned outwards an arrangement simi- 20 in any twoadjacent rollers is circular, the lar to that shown in Figure 5 isobtained. Again, 50 diameter of the circle being the same as that ofalternate sideplates having the platforms 30 may the holes to bedrilled. The rollersare hardened be placed on the other side of thechain so as to minimize Wear. The pitch of the rollers is to providestaggered holes in two rows more made equal to the pitch of the row ofholesto widely spaced. Another variant consists in probe drilled.v Sucha jig can be stretched over any viding the sideplates on both sides ofthe outer 55 links, or of the inner links, or both, with platforms 30which are outwardly turned thereby providing two rows of non-staggeredholes having a pitch equal to that of the chain or equal to one halfthat pitch, respectively. Other patterns of holes can be obtained, aswill be evident, by turning some of the platforms 3E! inwards.

It is evident that jigs according to this. invention may be used foroperation other than drilling, for example reaming, tapping, engravingand punching. In the case of engraving and punching the holes in thebushings may in some cases be non-circular.

I claim:

1. A flexible jig for use in drilling holes at equally spaced intervalson a curved surface, comprising a number of bushings and pivoted jointsconnecting said bushings together end to end.

2. A flexible jig according to claim 1 in which the joints compriseinner links and outer links jointed together by means of studs andbushing, and rollers mounted to rotate on the bushings joints consist ofouter links comprising sideplates connected together by studs, andblocks provided with transverse holes connecting together the studs ofsuccessive outer links.

4. A flexible jig for use in drilling holes at equally spaced intervalson a curved surface in the form of a standard transmission chain incombination with apertured blocks inserted between the sideplates of theinner links.

5. A flexible jig for use in drilling holes at equally spaced intervalson a curved surface, comprising side plates connected by pivoted jointsin the form of a transmission chain, certain sideplates havingextensions at one side bent over at right angles to the plane of thechain to provide platforms having holes and hardened bushings insertedin said holes. l

JAMES WEEDY.

